David Babson wrote:
>The directories probably won't be on-line, but you
might call the Dubuque historical society, and see if they have microfilmed
directories, available by interlibrary loan.<

Another possibility is your local Latter Day Saints ("Mormon") Family
History Center.  The location of the nearest one should be available on the
net.  The FHC can order the relevant records on microfilm from the LDS
library in Salt Lake City, and you can use them or make copies at the FHC. 
They specialize in these sorts of records, and are more likely than your
local library system to lay their hands on what you need.

A hint:  With directories, it may be best to swing wide.  Instead of 1900
to 1910, you might go with 1880 to 1930.  You won't need to look at each
year, but you can sample to narrow down beginning and end dates for the
company, address changes, etc., if you are interested in those.

Lauren Cook